1. Field of Invention
This invention relates to methods and apparatuses for transmitting signals, and more particularly to a method and apparatus where each transmitted signal is resent multiple times on the same frequency with a delay between each retransmission thus allowing for efficient use of a spectrum by the simultaneous use of one channel by various transmitters.
2. Description of Related Art
Heretofore a wide variety of methods and apparatuses have been proposed and implemented for transmitting multiple signals on the same frequency. One example is TDMA where each signal source is allocated a time interval on a frequency to transmit data. In this type of system, several sources use the same frequencies but are each allocated a unique time interval in which to transmit data. Another type of prior system is spread spectrum where, in one version the signal is simultaneously transmitted over several channels at once and summed together at the receiving end. Another example is CDMA which works by spreading a signal across a wide bandwidth using a spreading function. Each signal source uses a unique spreading function. The receive site uses the known spreading functions to decode each signal. Another system, Demand Assigned Multiple Access (DAMA) is used in satellite communications where a controller is used to assign a channel as needed for each transmitter to receiver communication.
The present invention is a unique and novel method with associated apparatus which allows multiple transmitters to simultaneously access the same channel at the same time. By allowing multiple transmitters to simultaneously access the same channel at the same time, increased and efficient use of the spectrum is achieved.
The present invention provides a method and apparatus for the more efficient transmission of data or voice signals in any given range of the electromagnetic spectrum, where each transmitted signal is resent multiple times on the same frequency with a delay between each retransmission. Multiple transmitters each transmit their repeated signals on the same channel at the same time. Any receiver can detect the desired transmission by making multiple copies of the incoming signal, delaying each copy by the reverse delay from the known delay set, and then summing the multiple time adjusted copies of the incoming signal. The method of the present invention is easily implemented and is highly efficient, effective, economical, and increases the use and potential of a data transmitting spectrum. It also allows multiple data signals to be transmitted on the same frequency.
Accordingly, it is the primary object of this invention to provide a method and apparatus for the simultaneous use of a channel in a communication spectrum by various transmitters where each transmitted signal may be resent multiple times on the same frequency with a unique preselected delay between each retransmission. Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claim.